The present invention concerns a device for controlling a display of an electronic watch capable of supplying two items of information of different types, comprising a selection circuit permitting the choice of the information to be displayed.
In particular, in electronic watches, several sorts of display are known which may be classified as a function of the frequency response thereof. There are two main types of display, namely, liquid crystal displays and light-emitting diode displays (LED).
The frequency response of electro luminescent diodes is very rapid; it is considered that a rise time or decay time of 10ns is a typical value.
The frequency response characteristic of the human eye is much inferior. Above approximately 30 Hz man can perceive no more than a continuous emission. This shows that the power consumed can be reduced by driving the display in a pulse mode.
To limit still further the consumption of current, watches have been designed the display of which is composed of only 4 digits; each digit being a 7 segment display with which it is possible to represent at least the Figures from 0-9. By means of these 4 digits it is possible to display either two sets of information, each comprising two digits, or three sets , one of which will occupy two digits, and the other two, the remaining two digits.
The object of the present invention is to provide a device by which it is possible to display different sets of information in one and the same display and making it possible to distinguish the nature of this display. This may concern, besides the indication of the time, a timed interval, a temperature, pressure, or even the result of the calculation of a small calculating machine.